Silphenylenes which have alkoxy groups on both terminals of the molecular chains include, for example, the compound expressed by the formula (CH.sub.3 O).sub.3 Si--C.sub.6 H.sub.4-- Si(OCH.sub.3).sub.3 (see Japanese Patent Application Kokai No. 6-41508). Furthermore, polymers consisting of silphenylene units and silethylene units include a polymer consisting of units expressed by the formula: ##STR2## (see Japanese Patent Application Kokai No. 4-325524).
A composition consisting of an organopolysiloxane resin and two types of alkoxysilanes is known as a curable silicone composition which is cured at room temperature to form a coating film (see Japanese Patent Application Kokai No. 51-148749). Furthermore, a composition consisting of an organopolysiloxane resin, an .alpha., .omega.-dihydroxydiorganosiloxane and an organosilane is known as a curable silicone composition which forms a cured coating film with water-repellent properties (Japanese Patent Application Kokai No. 55-48245). However, it cannot be said that these compositions have good curability; furthermore, these compositions suffer from the drawback of inferior storage stability. Moreover, in the case of these compositions, multiple coats are required in order to form a thick coating film.